Melee weapons cause low frame rate

[GZQRing]

I noticed that after melee weapon 2.9,most of melee weapon have been added some light effect that a little bit meaningless to me,what is important is that i couldn't cancel it.And after today(5/4)'s update,everytime i use melee weapon hit more than 2 or 3 enemies,the FPS will drop about 5 .It makes me really upset .😣

So can anyone tell me if  it's just a bug and it will be fixed,or any chance we can cancel it by ourserlves in the future,or it means i need to buy a new pc?😥